package pipe

import (
	"crypto/rand"
	"io/ioutil"
	"strings"
	"testing"
)

func Test_PipeReader_Bench(t *testing.T) {
	input := []byte(strings.Repeat("hello world", 1000))
	pr := New()
	pr.SetCap(1000)
	writing := func() {
		defer pr.Close()
		if n, err := pr.Write(input); err != nil {
			t.Errorf("failed to write: %v", err)
		} else if n != len(input) {
			t.Errorf("failed to write: wrote %v, expected %v", n, len(input))
		}
	}
	reading := func() {
		if bytes, err := ioutil.ReadAll(pr); err != nil {
			t.Errorf("failed to read: %v", err)
		} else if len(bytes) != len(input) {
			t.Errorf("failed to read: read %v, expected %v", len(bytes), len(input))
		}
	}
	go writing()
	reading()
}

func Test_PipeReader(t *testing.T) {
	cases := []struct {
		streamLength int
		bufferCap    int
	}{
		{
			streamLength: 10000000,
			bufferCap:    50,
		},
		{
			streamLength: 1000000,
			bufferCap:    5000,
		},
		{
			streamLength: 100,
			bufferCap:    50,
		},
		{
			streamLength: 50,
			bufferCap:    100,
		},
		{
			streamLength: 10,
			bufferCap:    5,
		},
		{
			streamLength: 5,
			bufferCap:    10,
		},
		{
			streamLength: 1,
			bufferCap:    10,
		},
		{
			streamLength: 0,
			bufferCap:    10,
		},
	}

	for _, c := range cases {
		pr := New()
		pr.SetCap(int64(c.bufferCap))
		input := make([]byte, c.streamLength)
		if _, err := rand.Read(input); err != nil {
			t.Fatalf("cannot read random bytes: %v", err)
		}
		go func() {
			defer pr.Close()
			n, err := pr.Write(input)
			if n != c.streamLength || err != nil {
				t.Errorf("ERR: failed to write %v bytes to %v cap: %v", c.streamLength, c.bufferCap, err)
			}
			t.Logf("wrote %v bytes to pipereader", n)
		}()
		output, err := ioutil.ReadAll(pr)
		if err != nil {
			t.Errorf("ERR: failed to read %v bytes to %v cap: %v", c.streamLength, c.bufferCap, err)
		} else if string(output) != string(input) {
			t.Errorf("ERR: sl=%v, bc=%v, read wrong output from pipe: \nwanted %v, \n   got %v", c.streamLength, c.bufferCap, len(input), len(output))
		}
		t.Logf("read %v bytes from pipereader", len(output))
	}
}